|Loan, R - TEXAS A&M UNIV.-CLGE STN|
|Straus, D - TEXAS TECH UNIV.-LUBBOCK|
Submitted to: American Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 27, 1999
Publication Date: November 1, 2000
Citation: Purdy, C.W., Loan, R.W., Straus, D.C., Briggs, R.E., Frank, G.H. 2000. Conglutinin and immunoconglutinin titers in stressed calves in a feedlot. American Journal of Veterinary Research. 61(11):1403-1409. Interpretive Summary: Market stressed feeder calves. when moved to the feedyards, frequently become sick with respiratory tract disease (RTD) which costs the feeder calf industry over $750 million dollars per year in treatment time, medicine, chronic illness and death. The cause of the disease is very complex; it includes multiple stressors, virus infections of the upper respiratory tract, and is usually followed by bacterial infections of the Pasteurella group. The calves' immune response to this disease is just as complex. Part of the immune response involves potential conglutinin activity which is part of non-specific immunity, however conglutinin activity has never been studied in market-stressed calves with RTD nor has immunoconglutinin antibodies been studied in market-stressed calves recovering from RTD. We studied the conglutinin and immunoconglutinin response in 101 feeder calves moved from eastern TN to northwest TX where 72% of them developed upper RTD. It does not appear that calf mean conglutinin concentration plays a significant role in reducing acute bovine RTD. However, conglutinin concentration was significantly different in calves originating from different farms. Increasing immunoconglutinin titers appear to be related to the recovery of market-stressed calves from RTD during the first 15 days in the feedyard. This adds another piece to the immunity puzzle for the scientific understanding of bovine immunity to RTD.
Technical Abstract: Conglutinin and immunoconglutinin activity in market-stressed feeder calves was analyzed to determine if they played a role in the prevention of bovine respiratory tract disease (BRTD) or in the recovery of calves from acute BRTD. Haptoglobin and fibrinogen inflammatory markers were also analyzed. One hundred and one British light weight mixed-bred calves were purchased from four farms in eastern Tennessee. The calves were processed and returned to their dams for 100 days. Afterwards, all calves were brought to a centrally located order buyer barn (OBB) where they were processed and then shipped to a research feedlot in Bushland, Texas. The calves were sorted to pens and observed daily for clinical signs of acute BRTD. When sick calves were found, they were treated with antibiotics and isolated in sick pens for four days. Calves were weighed and bled on the farms, at the OBB and weekly for four weeks in the feedlot for serum. Nasal swabs were collected on the same sampling days. While in the feedlot, 72% of the calves developed acute BRTD and 28% remained healthy. Haptoglobin concentration appears to be a better marker of inflammatory disease for calves than fibrinogen over four days in the sick pen. It does not appear that calf mean conglutinin concentration played a significant role in reducing acute BRTD or in the recovery from the disease. Increasing immunoconglutinin titers appear to be related to the recovery of calves from BRTD during the first 15 days in the feedlot.